1. Field of the Invention
The present invention relates to the field of surgery and, in particular, to a shoulder model and methods of shoulder arthroscopy using the shoulder model.
2. Description of the Related Art
A human shoulder includes 3 bones—the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone)—and two joints. The joints are the acromioclavicular (AC) joint and the glenohumeral joint, which is the traditional “ball-and-socket.” The bones of the shoulder are held together by muscles, tendons (attach muscles to bones), and ligaments (attach bones to bones).
The “rotator cuff” is used to describe the group of muscles and their tendons in the shoulder that hold the “ball” (the humeral head) in the “socket” (the glenoid) and helps control the shoulder joint motion. The muscles—supraspinatus at the top (superior) of the shoulder, subscapularis in the front (anterior), and infraspinatus and teres minor behind (posterior)—insert or attach to the humeral head by way of their tendons. These muscles help keep the ball centered within the socket.
Above the rotator cuff is a bony projection from the scapula (shoulder blade) called the acromion. The acromion forms the “ceiling” of the shoulder, serves as the point of origin for the deltoid muscle, and joins the clavicle (collarbone) to form the acromioclavicular (AC) joint. Between the rotator cuff tendons and the acromion is a protective fluid-filled sack called “bursa.”
Other terms used in describing the anatomy of a shoulder are: “capsule” (a pocket that provides stability); and “labrum” (a rim of cartilage to which the capsule attaches).
Tears may be located either superior or inferior to the middle of the glenoid socket. A superior labrum anterior-posterior (SLAP) lesion is a tear of the rim above the middle of the socket that may also involve the biceps tendon. A Bankart lesion is a tear of the rim below the middle of the glenoid socket that also involves the inferior glenohumeral ligament. Typically, rotator cuff tears occur in the supraspinatus but other muscles—subscapularis, infraspinatus, and teres minor—may also be involved.
The arthroscopic anatomy of a shoulder joint is typically divided into five regions: anterior (nose-end), posterior (tail-end), superior (head-end), inferior (feet-end), and central. The posterior approach to the shoulder provides better orientation and the widest field of view amongst all of the approaches. On the other hand, the superior approach may cause damage to a critical area of supraspinatus tendon and its application is typically not recommended.
Generally, arthroscopic procedures are experimented on fresh cadaver specimens. In many instances, however, cadaver specimens may be unavailable or even undesirable as a biohazard.
Thus, there is a need for a shoulder model that enables a surgeon to practice open surgical procedures and arthroscopic procedures in a clean and dry setting, to perform the procedure with repeatability by placing arthroscopic cannulas, and to use in lieu of cadaver specimens. There is also a need for a shoulder model that replicates the features of a human shoulder and can be easily transported, assembled, and refurbished with new components.